Raising of natural oil and other liquids by gaseous pressure



Oct. 24, 1950 2,526,801

N. F. BROWN RAISING OF NATURAL OIL AND OTHER LIQUIDS BY GASEOUS PRESSURE Filed Jan. 6, 1947 Patented Oct. 24, 1950 RAISING OF NATURAL OIL AND OTHER LIQUIDS BY GASEOUS PRESSURE Norman Fraser Brown, London, England Application January 6, 1947, Serial No. 720,412 In Great Britain July 22, 1946 Claims.

The present invention relates primarily to the raising of liquid in wells by displacement pumping apparatus of the kind comprising a displacement chamber adapted to be located below liquid level in the well and an eduction pipe vertically reciprocating in said chamber and adapted to be moved into one position to isolate the chamber from the well and connect it with the eduction pipe to permit liquid collected in said chamber to be forced by gaseous pressure up the eduction pipe, the pipe being adapted to be moved into another position to shut off the supply of gaseous pressure, connect the .interior of the chamber with the well to permit liquid to flow into the chamber and isolate the chamber from the eduction pipe.

Whilst the invention is particularly applicable to raising natural oil, it will be understood that the invention may be applied to raising other liquids.

It is necessary to control the operational cycle of the displacement pump and heretofore this has been done by an electrical timing device adapted to be preset to actuate a valve which controlled the admission of fluid pressure to raise the eduction pipe and after a predetermined interval of time to actuate means for exhausting the fluid pressure to allow the eduction pipe to descend. A drawback of such timing mechanism is that it has to be preset, at the start of pumping operations, to terminate every operational cycle of the pump after the same fixed period of time. This preset period will not be ideal for each cycle, as the period is necessarily calculated to allow for the possible variation of several factors which may influence the time required for the liquid to be raised to the surface of the well.

It is an object of the present invention to provide means to overcome this drawback.

According to the present invention the movement of the eduction pipe of the apparatus to the first-mentioned position is initiated by electrically controlled means and the movement of the eduction pipe into the second mentioned position is initiated by means actuated by the liquid forced up the eduction pipe when the pipe is in the first mentioned position. The pipe may be raised into the first position and released by the liquid actuated means to descend to the second mentioned position. The liquid actuated means may comprise a diaphragm or other pressure responsive device adapted to be actuated by the pressure of the liquid flowing in or from the eduction pipe, to release trip mechanism.

,of which forms the base of cylinder 6.

To enable the invention to be fully understood it will now be described with reference to the drawing accompanying the specification which shows a schematic view of apparatus embodying one form of the present invention.

As shown, I is an oil well casing the lower end of which, not shown, would be perforated to admit oil from the surrounding strata. The upper end of the casing is closed by a casing head 2 which supports a pipe 3 which extends through an aperture in the head 2 into the casing i. A pipe 4 is provided for carrying oif low pressure gas from the casing.

The pipe 3 supports a cylinder 5 the upper end A piston I is reciprocably mounted in the cylinder 6 and has hollow rods 8 and 9 which respectively extend through packings in the base and top of the cylinder 6, the upper end of the rod 9 engaging a collar it on an oil eduction pipe I I for :raising it. The pipe H extends through packings 45 in hollow rod 9 and through the hollow .rods 8, 9 piston l and interiorly of the cylinder 5 and pipe 3 down into the well. A series of rings I2 are provided on the upper face of the piston I to limit the upward stroke of the piston. The effective stroke being preset to suit particular .well conditions by adding or removing rings.

The upper end of the cylinder 6 is connected with the low pressure gas in the well casing by a pipe l3 and the cylinder 5 is connected with a source of high pressure gas by a pipe 14.

An electromagnetically controlled valve unit A is provided for initiating the pump cycle, the unit comprising a coil 15 connected by leads 16 with a current supply, and a loosely fitting armature I! normally urged to close on a valve seat I8 by a spring IS. To initiate a cycle a switch is closed to energise the coil l5 and maintain it energised for a predetermined short period, for example 30 seconds. When the coil I5 is energised, the armature I1 is raised to uncover the valve seat [8 and close on a valve seat 2!]. When the valve seat I8 is uncovered gas under high pressure flows from the pipe 2! connected with pipe 14, into pipe 22 and enters an auxiliary cylinder 23 through a restricted passage 24.

The cylinder 23 contains a piston 25 which is depressed by the pressure of the inflowing gas to force liquid, for example oil, from the cylinder through the pipe 26 into the valve casing 2'1 where it lifts the check valve 28 and flows through the pipe 29 to the cylinder 6 to lift the piston I and raise the eduction pipe ll. When the piston I has been fully raised the check valve 23 will be closed by its spring to trap the oil beneath the piston l and so maintain the piston I in raised position indefinitely until the check valve is reopened. An important advantage of this feature is that the accidental lowering of the piston 1 due to failure of gas pressure acting on the piston is prevented and the possibility of the pump becoming liquid jammed due to the eduction pipe being lowered to refilling position before the slug in the pipe is produced, is prevented.

The high pressure gas in the pipe 22 also flows to the valve casing 2i above a piston and forces this outwardly of its cylinder to depress a pivoted trip lever 3| against its actuating spring 32 until a roller 33 is positioned beneath an abutment 34, to hold the trip in set position. The trip mechanism is fully described in co-pending application Serial No. 767,947 which matured into Patent No. 2,515,291, dated July 18, 1950.

The current to the coil I5 is switched ofl after a predetermined short period, for example 30 seconds, and the coil being de-energised, the armature drops to close on the valve seat l8 and uncover the valve seat 29. Accordingly the supply of high pressure gas to the pipe 22 is cut off and this pipe is connected through slots in the armature I7 to the pipe leading to the low pressure pipe 4, and the space above the piston 30 is exhausted and high pressure gas in the cylinder 23 commences to exhaust but at a slower rate, due to the presence of the choke passage 24.

Another advantage of relieving the pressure above the piston 25 coupled with the use of check valve 28 to hold the main piston l in the raised position is that the descent of piston l and tubing commences instantaneousl with the opening of valve 28 on the arrival of the top of the liquid slug at surface and effects the shutting off of pressure gas supply to the displacement chamber at the bottom of the well a few seconds later; whereas if gas pressure is maintained above piston 25 until the arrival of the top of the slug, there is an objectionable time delay while this pressure. which in the first instance is appreciably in excess of that required to cause the raising of the tubing falls to that value at which the main piston I and the tubing can commence to descend and is followed by a comparatively slow descent.

The apparatus remains in the position shown in the accompanying drawing during the period in the pump cycle while a slug of liquid is lifted up the pipe I l by gaseous pressure.

The slug of oil raised in each cycle flows through the flexible connecting pipe 36 to a chamber 31 having a restriction formed by an inwardly directed wall 38 and after leaving the chamber enters a pipe 39 which delivers it to oil collecting means. The chamber 31 may be an integral part of the valve casing 27. A flexible diaphragm 40 is mounted in the chamber 3'! and normally maintained in the position shown in the drawing to provide a restricted passage through the chamber. A passage 4! connects the rear of the diaphragm with the pipe 39.

The rear face of the diaphragm carries a push rod 42 the outer end of which is adapted to engage the trip lever 3| and the opposite face of the diaphragm is provided with a rod 43 extending through the wall 38 to permit manual operation of the diaphragm for testing.

The arrangement of the chamber 3'! is such that any gas preceding the slug of oil raised in each cycle flows past the diaphragm without actuating it. On arrival of the slug of oil, however, due to the restricted passage, a differential pressure across the diaphragm is set up and the diaphragm is forced away from the wall 38. The effect of the differential pressure is augmented by the oil being forced to change direction towards the diaphragm by the inwardly directed wall 38. Displacement of the diaphragm releases the trip mechanism by forcing the push rod 42 to rock the trip lever and disengage the roller 33 from underneath its abutment 34. When released the spring 32 snaps the lever 3i upwardly, and the piston 38 is raised to lift the check valve 28 from its seat thereby permitting the fluid trapped beneath the main piston l to flow back to the auxiliary cylinder 23 so that the piston 1 is free to descend into refilling position to complete the operational cycle of the pump.

As the gas pressure in the cylinder 23 has been partially relieved, the main piston 1 will fall rapidly at first but due to the choke passage 24 there will be suflicient rise in pressure of the gas in the cylinder 23 to cushion the upward stroke of the piston 25 and so retard the final portion of the stroke of the piston I and prevent jarring or possible damage to the apparatus due to too rapid a descent.

It will be noted that the diaphragm provides only a temporary restriction in the chamber 31 as, when it is displaced by the slug of oil, there will be sufficient space in the chamber for free flow of the oil; the diaphragm is maintained in displaced position by the pressure of the flowing oil.

It will be understood that the arrangement is such that the diaphragm will not be actuated by the direct pressure of the liquid or gas but is actuated solely by the differential pressure set up as the liquid flows past the diaphragm. The necessary differential pressure to actuate the diaphragm to release the trip mechanism is accordingly independent of the actual gauge pressure in the liquid flow line. The gas flowing in the eduction pipe in front of the slug of liquid will be of such low specific gravity, as compared with that of the liquid, that the gas is incapable of setting up the necessary differential pressure to actuate the diaphragm.

By providing means controlled by the arrival at the surface of the slug raised in each cycle, to initiate the descent of the eduction pipe, the eduction pipe will be lowered into refilling position ready for the start of another cycle of operations a few seconds after the arrival at surface of the top of the slug of the preceding cycle, the remainder of the slug being produced by the expansional use of the gas then in the eduction pipe ll underneath it.

This is not possible where the duration of each cycle is controlled by means such as timing devices as such devices have to be preset to allow for possible variations of several factors which are likely to influence the time required for a slug of oil to reach the top of the well. The presetting of the timin device is necessarily of an arbitrarv nature and is obviously not ideal for each cycle.

In the present arrangement wherein the arrival of the slug itself determines the duration of the cycle, the lowering of the eduction pipe is effected precisely and automatically at the correct time for each cycle.

The invention also makes possible a valuable simplification of the electrical switching mechanism which no longer is required to predetermine the duration of each cycle and in consequence the supervisory work for the control of a large number of wells in a field is advantageously reduced and simplified.

I claim:

1. In a displacement, pumping apparatus of the kind referred to, a reciprocably mounted liquid eduction pipe, means for raising said pipe into one operative position and holding it in raised position, means for releasing said pipe to fall by gravity into a second operative position, a flow pipe connected with the upper end of said eduction pipe for receiving the liquid raised up the eduction pipe, a device mounted in said flow pipe to form a displaceable restriction to the flow of liquid through said flow pipe, said device being adapted to be actuated by the differential pressure set up by liquid flowing past it, means connecting said device with said release means for actuating the release means to effect the movement of the eduction pipe into its second operative position upon the device being displaced by the differential pressure set up by liquid flowing past it through said flow pipe.

2. In a displacement pumping apparatus of the kind referred to, a reciprocably mounted liquid eduction pipe, means for raising said pipe into one operative position and holding it in raised position, means for releasing sad pipe to fall by gravity into a second operative position, a flow pipe connected with the upper end of said eduction pipe for receiving the liquid raised up the eduction pipe, a flexible diaphragm mounted within said flow pipe and normally flexed inwardly to form a temporary restriction to the flow of liquid flowing through said flow pipe and means connecting said diaphragm with said release means to actuate the same when said diaphragm is flexed outwardly by the differential pressure set up by liquid flowing past it through said flow pipe.

3. In a displacement pumping apparatus of the kind referred to for raising liquid in wells by gaseous pressure, a reciprocably mounted liquid eduction pipe, means for moving said pipe into one operative position, means for holding said pipe in said position, means for releasing said holding means to permit the pipe to descend to a second operative position, a flow pipe connected with the upper end of said eduction pipe for conveying liquid raised up the eduction pipe,

a member having a liquid flow passage extending axially therethrough, one end of said flow passage being connected with said flow pipe, a delivery pipe connected with the opposite end of said flow passage, an inwardly extending projection on the inner wall of said flow passage in said member, a flexible diaphragm mounted in said member opposite said projection, means normally flexing said diaphragm toward said projection to form a temporary restriction to the flow of liquid through the flow passage of said member, means connecting said diaphragm with the releasing means for actuating the same upon the diaphragm being flexed outwardly by the diflerential pressure set up by liquid flowing from the said flow pipe and past the said diaphragm in said member.

4. In a displacement pumping apparatus of the kind referred to for raising liquid in wells by gaseous pressure, a reciprocably mounted liquid eduction pipe, means for moving said pipe into one operative position, means for holding said pipe in said position, means for releasing said holding means to permit the pipe to descend to a second operative position, a

flow pipe connected with the upper end of said eduction pipe for conveying liquid raised up the eduction pipe, a member having a liquid flow passage extending axially therethrough, one end of said flow passage being connected with said flow pipe, a delivery pipe connected with the opposite end of said flow passage, an inwardly extending projection on the inner wall of said flow passage in said member, a flexible diaphragm mounted in said member opposite said projection with the major part of the front face of said diaphragm directed upstream relative to said projection in said member, means connecting the rear face of said diaphragm with the flow passage in said member on the downstream side of said projection, said front and rear faces of the diaphragm having equal areas, means normally flexing said diaphragm toward said projection to form a temporary restriction to the flow of liquid through the flow passage of said member, means connecting said diaphragm with the releasing means for actuating the same upon the diaphragm being flexed outwardly by the differential pressure set up by liquid flowing from the said flow pipe and past, the said diaphragm in said member.

5. In a displacement pumping apparatus of the kind referred to, a reciprocably mounted liquid eduction pipe, means for raising said pipe into one operative position and holding it in raised position, pre-loaded spring trip means for releasing said pipe to fall by gravity into a second operative position, a flow pipe connected with the upper end of said eduction pipe for receiving the liquid raised up the eduction pipe, a device mounted in said flow pipe to form a displaceable restriction to the flow of liquid through said flow pipe, said device being adapted to be actuated by the differential pressure set up by liquid flowing past it, means connecting said device with said trip means for actuating same to effect the movement of the eduction pipe into its second operative position upon the device being displaced by the differential pressure set up by liquid flowing past it through said flow pipe.

6. The apparatus of claim 2 wherein the means for releasing said eduction pipe to fall to its second operative position comprises ore-loaded spring tip means operatively connected with said flexible diaphragm.

'7. In a displacement pumping apparatus of the kind referred to, a reciprocably mounted liquid eduction pipe, a piston operatively connected with the eduction pipe, means for supplying liquid under pressure to said piston to raise said eduction pipe into one operative position, means for trapping said pressure liquid beneath said piston to maintain the eduction pipe in raised position, means for releasing said pipe to fall by gravity into a second operative position, a flow pipe connected with the upper end of said eduction pipe for receiving the liquid raised up the eduction pipe, a device mounted in said flow pipe to form a displaceable restriction to the flow of liquid through said flow pipe, said device being adapted to be actuated by the differential pressure set up by liquid flowing past it, means connecting said device with said release means for actuating the release means to effect the movement of the eduction pipe into its second operative position upon the device being displaced by the differential pressure set up by liquid flowing past it through said flow pipe.

8. In a displacement pumping apparatus of the kind referred to, a reciprocably mounted liquid eduction pipe, a piston operatively connected with the eduction pipe, a cylinder for said piston, means for supplying liquid under pressure to said cylinder to raise the piston and move the eduction pipe into one operative position, means for automatically trapping said pressure liquid in said cylinder to maintain the pipe in raised position, means to release said trapped liquid to permit the said eduction pipe to mov to a second operative position, pre-loaded spring trip means for operating said release means, a flow pipe connected with the upper end of said eduction pipe for receiving the liquid raised up the eduction pipe, a device mounted in said flow pipe to form a displaceable restriction to the flow of liquid through said flow pipe, said device being adapted to be actuated by the diiferential pressure set up by liquid flowing past it, means con meeting said device with said trip means for actuating same to eflect the movement of the eduction pipe into its second operative position upon the device being displaced by the difierential pressure set up by liquid flowing past it through said flow pipe.

9. In a displacement pumping apparatus of the kind referred to, a reciprocably mounted liquid eduction pipe, a piston operatively connected with said eduction pipe, a cylinder for said piston, an'auxiliary cylinder containing hydraulic liquid, a supply line connecting said first-mentioned cylinder with said auxiliary cylinder, means for supplying gas under pressure to said auxiliary cylinder to displace the hydraulic liquid from said auxiliary cylinder into said first mentioned cylinder to raise the piston and the eduction pipe operatively connected with said piston, valve means in said supply line which when closed traps part of the hydraulic liquid in said first-mentioned cylinder to maintain the piston and eduction pipe in raised position, a flow pipe connected with the upper end of said eduction pipe for receiving the liquid raised up the eduction pipe, a device mounted in said flow pipe to form a displaceable restriction to the flow of liquid through said flow pipe, said device being adapted to be actuated by the differential pressure set up by liquid flOWiIlg past it, means actuated upon displacement of the device for opening said valve means to release said trapped hydraulic liquid, and to efiect the movement of the eduction pipe into a second operative position, and a vent in said auxiliary cylinder for venting the gas pressure in said auxiliary cylinder to permit a relatively rapid return flow of the hydraulic liquid from the first-mentioned cylinder into the auxiliary cylinder when said valve means is opened.

10. In a displacement pumping apparatus of the kind referred to, a reciprocably mounted liquid eduction pipe, means for raising said pipe into one operative position and holdin it in raised position, trip means and pro-loaded actuating spring for releasing said pipe to fall by gravity into a second operative position, fluid pressure operating means for resetting the trip mechanism and reloading its actuating spring, a flow pipe connected with the upper end of said eduction pipe for receiving the liquid raised up the eduction pipe, a device mounted in said flow pipe to form a displaceable restriction to the flow of liquid through said flow pipe, said device being adapted to be actuated by the diiferential pressure set up by liquid flowing past it, means connecting said device with said trip means for actuating same to effect the movement of the eduction pipe into its second operative position upon the device being displaced by the difierential pressure set up by liquid flowing past it through said flow pipe.

NORMAN FRASER BROWN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,162,418 Brown June 13, 1939 2,265,099 Chenault Dec. 2, 1941 2,515,291 Brown July 18, 1950 

